Lead pointing device



Oct. 13, 1964 A. H. KENT LEAD POINTING DEVICE Filed June 20, 1962 INVENTOR. AME/V ms/vr I BY 7 6M QW- United States Patent 3,152,581 LEAD POINTING DEVICE Allen H. Kent, New York, N.Y., assignor to Landers, Frary 8: Clark, New Britain, Conn., a corporation of Connecticut Filed June 20, 1962, Ser. No. 203,868 3 Claims. (Cl. 120-96) The instant invention relates to devices for sharpening pencil lead and more particularly to a power device of this type.

Persons such as architects, draftsmen, engineers and such, utilize mechanical pencils requiring leads having sharp, smooth points. Even though the leads are relatively hard, the points are soon dulled so that frequent sharpening is required.

Traditionally, lead points have been kept sharp by the utilization of sandpaper. In addition to being messy and time consuming, the utilization of sandpaper does not result in points of uniform shape and precision. Moreover, the lead dust produced by sandpapering is likely to soil the hands of the user and to smudge the drawings.

Another prior art method for pointing pencil leads comprises a mechanical sharpener device of the type illustrated by US. Patent No. 2,557,646 issued June 19, 1961. While the device of this patent often produced a satisfactory point, a considerable amount of skill was required on the part of the user in order to avoid lead breakage. Even with a skilled worker manipulating this device, lead pointing was a time consuming operation.

The device of the instant invention overcomes all of the disadvantages of prior art devices by providing a lead sharpener device which is power operated. The device includes a receptacle to receive the lead scrappings with the receptacle being rotatable by means of a battery operated motor. The receptacle is provided with a removable cover which rotates in unison therewith. Disposed within the receptacle is a holder containing a plurality of lead sharpener blades.

The blade holder is mounted to a plate which is free to move vertically being guided by two vertically extending rods which are connected to the cover by means of a floating mounting including means defining transverse horizontal axes for the blade holder. Compression springs mounted to the rods bias the blade holder toward the cover.

For sharpening, the lead is moved axially downward into the blade holder by an amount sufiicient to cause the springs to be slightly compressed. This automatically causes the motor controlling circuit to be energized to bring about rotation of the receptacle. As the receptacle rotates the blade holder, hence the blades rotate to sharpen the lead. The spring biases the sharpener blades into engagement with the lead with a force less than that required to break the lead. Any vertical misalignment is compensated for by the floating mounting thereby assuring that the lead will not be subjected to any undue transverse strain.

Accordingly, a primary object of this invention is to provide a lead pointing device which is more easily operable and more reliable than similar devices of the prior art.

Another object is to provide a novel power operated lead sharpening device.

Still another object is to provide a lead sharpening device in which the blade holder is biased toward a mounting member and is also mounted for limited rotation with respect to said member about a pair of transverse axes.

A further object is to provide a lead pointing device in which the scraper blades are mounted to a floating mounting secured to the inside of the removable cover of a rotatable receptacle.

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These as well as other objects of this invention shall become readily apparent after reading the following description of the accompanying drawings in which:

FIGURE 1 is a transverse cross section of the power operated lead sharpener device of this invention.

FIGURES 2 and 3 are cross sections taken through line 22 looking in the direction of arrow 22. In FIGURE 2 the elements are shown in their positions when the device is not in use while in FIGURE 3 the elements are shown in their positions when the device is being utilized to sharpen lead which is poorly aligned with respect to the rotational axis for the receptacle.

FIGURE 4 is an exploded perspective of the receptacle cover and the elements carried thereby.

FIGURE 5 is a side elevation of the cover and elements carried thereby with many of the elements partially sectioned to reveal internal formations thereof.

FIGURE 6 is a bottom view of the spring element which provides the floating mount connection between the cover and the blade holder.

FIGURE 7 is a plan view of the blade holder.

For detailed descriptions of any of the elements hereinafter noted, reference is made to my US. Patent No. 3,004,522, issued October 17, 1961, and my co-pending application, Serial Number 43,841, filed July 19, 1960.

Now referring to the figures. Lead pointing device 10 includes base 11 and cover 12 cooperating to form a housing within which most of the other elements are disposed. Speed reducing gear train 13 is mounted between and supported by base 11 and plate 14 positioned parallel to base 11. Drive motor 15 is mounted to the top of plate 14 with the motor output shaft extending downward through an aperture in plate 14 to drive pinion 16 which in turn provides the high speed input for gear train 13.

The energization for motor 15 is provided by a plurality of serially connected dry cells 17 electrically connected by suitable straps 18 mounted between base 11 and top plate 19 which is positioned above plate 14 and is parallel to base 11. Contact elements 20, 21 on the top side of plate 14, form a normally open switch in the energizing circuit for motor 15. Contact element 20 is self-biased away from engagement with element 21 and provides a seat for collar 22 extending from the bottom of receptacle 25. Transmission output shaft 23 is fixedly secured to collar 22 by set screw 24. Thus, it is seen that rotation of shaft 23 brings about rotation of receptacle 25.

The upper end of receptacle 25 extends through aperture 26 in cover 12 with removable receptacle cover 30 being threadably mounted to receptacle 25 at the upper end thereof and positioned externally of housing cover 12. Screw means 27 extends through a clearance aperture in cover 12 and is received by a threaded aperture of top plate 19 to secure cover 12 in place.

Screws 31 passing through clearance apertures 32 in cover 30 and clearance apertures 33 in the inward extensions 34 of annular spring member 35 and cooperate with nuts 36 to fixedly secure resilient annular member 35 to cover 30. Nuts 37 and 38, positioned on opposite sides of inward extensions 39 of annular member 35, are in threaded engagement with the upper ends of guide rods 40. These upper ends of rods 40 extend through clearance apertures 41 of inward radial extensions 39 of member 35. It is noted that member 35 normally maintains guide rods 40 parallel to shaft 23 which comprises the rotation axis for receptacle 25.

Guide rods 40 pass through clearance apertures 42 in plate 43 and clearance apertures 44 in plate 45. Member 46 is provided with tapered guide seat and central opening 47 extending therethrough and is also provided with a lower portion 48 force fitted within central aperture 49 of plate 43. Plastic blade holder 50 is force fitted within central aperture 51 of blade 45. Compression springs 52 mounted to guide rods 40 below plate 45 are maintained in position by means of nuts 53 secured to the lower threaded ends of guide rods 40. Blade holder 50 positions a plurality of radially extending scraper blades in the manner particularly illustrated in the aforesaid US. Patent 2,557,646. Holder 50 is also provided with side apertures 54 to permit lead scrapings to fall into receptacle 25.

With particular reference to FIGURE 3, lead sharp ener device 70 is operated by inserting the leaded end of pencil 60 through central aperture 61 of cover 30, through seating aperture 47 of member 46 and central aperture 63 in the top of blade holder 50. As the lower end of the lead engages the blades Within holder 50, holder 50 hence plate 45 is forced downward thereby compressing bias springs 52. At the same time, receptacle 25 is moved bodily downward forcing contact member 20 into engagement with contact member 21 thereby closing the energizing circuit for motor 15 to cause about rotation thereof. Motor 15 acting through gear train 13 causes receptacle 25 to rotate about shaft 23 as an axis. The cooperating threads between cover 30 and receptacle 25 are so arranged that cover 30 rotates about a somewhat vetrical axis of all members carried by cover 30.

Inward extensions 34 of spring member 35 define one substantially horizontal pivotal axis for blade holder 50 while inward extensions 39 form a second substantially horizontal pivotal axis for blade holder 50. These axes are positioned transverse to one another with the first mentioned axis being disposed above the second mentioned axis.

With the construction hereinbefore described, it has been found that even with considerable movement of pencil 60 during the sharpening operation and even if the lead is badly misaligned with respect to the axis of rotation for receptacle 25, lead breakage will not occur. With blade holder 50 in its most upward position of FIGURE 2, springs 52 are somewhat compressed. So long as springs 52 are not bottomed, it is the spring force alone which acts along the longitudinal axis of the lead. Springs 52 are so proportioned that the lead can safely withstand the spring forces yet these forces are sufficient to bias the blades within the holder 50 against 4 the lead with sufiicient force to produce an effective sharpening action.

Thus, this invention provides a novel construction for a power driven lead sharpening device. The construction of the device is such that breakage of lead is reduced to a minimum and sharpening time is materially reduced without the user requiring any special skill.

Although I have described preferred embodiments of my novel invention, many variations and modifications will now be obvious to those skilled in the art, and I prefer therefore to be limited not by the specific disclosure herein but only by the appended claims.

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows:

1. In a pencil sharpener a motor driven receptacle mounted for rotation on its axis which is fixed, a blade holder attached to and lying in said receptacle, and means for supporting said blade holder on said axis when unstressed including guide means on which said blade holder is mounted and may slide along said axis, springs for resisting such sliding movement under the pressure of a pencil inserted into said blade holder, and resilient means for interconnecting said guide means to said receptacle while permitting said guide means to tilt with respect to said axis when the applied force of the inserted pencil causes tilting.

2. In the combination of claim 1, said resilient means comprising a ring of resilient material and means for securing said ring to said receptacle and to said guide means.

3. In the combination of claim 1, said resilient means comprising a ring of resilient material having two pairs of inward extensions and means for securing one pair of extensions to said receptacle and the other pair to said guide means.

References Cited in the file of this patent UNITED STATES PATENTS 2,769,428 Onanian Nov. 6, 1956 3,004,522 Kent Oct. 17, 1961 FOREIGN PATENTS 297,445 Switzerland June 1, 1954 331,725 Italy Nov. 13, 1935 

1. IN A PENCIL SHARPENER A MOTOR DRIVEN RECEPTACLE MOUNTED FOR ROTATION ON ITS AXIS WHICH IS FIXED, A BLADE HOLDER ATTACHED TO AND LYING IN SAID RECEPTACLE, AND MEANS FOR SUPPORTING SAID BLADE HOLDER ON SAID AXIS WHEN UNSTRESSED INCLUDING GUIDE MEANS ON WHICH SAID BLADE HOLDER IS MOUNTED AND MAY SLIDE ALONG SAID AXIS, SPRINGS FOR RESISTING SUCH SLIDING MOVEMENT UNDER THE PRESSURE OF A PENCIL INSERTED INTO SAID BLADE HOLDER, AND RESILIENT MEANS FOR INTERCONNECTING SAID GUIDE MEANS TO SAID RECEPTACLE WHILE PERMITTING SAID GUIDE MEANS TO TILT WITH RESPECT TO SAID AXIS WHEN THE APPLIED FORCE OF THE INSERTED PENCIL CAUSES TILTING. 